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ARM: kprobes: Add Thumb instruction decoding stubs

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Extend arch_prepare_kprobe to support probing of Thumb code. For
the actual decoding of Thumb instructions, stub functions are
added which currently just reject the probe.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
This commit is contained in:
Jon Medhurst 2011-04-19 17:56:58 +01:00 committed by Tixy
parent de41984003
commit 2437170710
4 changed files with 61 additions and 2 deletions
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4
arch/arm/kernel/Makefile
View File

@ -38,7 +38,11 @@ obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
obj-$(CONFIG_KPROBES) += kprobes.o kprobes-common.o
ifdef CONFIG_THUMB2_KERNEL
obj-$(CONFIG_KPROBES) += kprobes-thumb.o
else
obj-$(CONFIG_KPROBES) += kprobes-arm.o
endif
obj-$(CONFIG_ATAGS_PROC) += atags.o
obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o
obj-$(CONFIG_ARM_THUMBEE) += thumbee.o

26
arch/arm/kernel/kprobes-thumb.c Normal file
View File

@ -0,0 +1,26 @@
/*
* arch/arm/kernel/kprobes-thumb.c
*
* Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include "kprobes.h"
enum kprobe_insn __kprobes
thumb16_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
return INSN_REJECTED;
}
enum kprobe_insn __kprobes
thumb32_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
return INSN_REJECTED;
}

20
arch/arm/kernel/kprobes.c
View File

@ -51,16 +51,32 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
kprobe_opcode_t insn;
kprobe_opcode_t tmp_insn[MAX_INSN_SIZE];
unsigned long addr = (unsigned long)p->addr;
kprobe_decode_insn_t *decode_insn;
int is;
if (addr & 0x3 || in_exception_text(addr))
if (in_exception_text(addr))
return -EINVAL;
#ifdef CONFIG_THUMB2_KERNEL
addr &= ~1; /* Bit 0 would normally be set to indicate Thumb code */
insn = ((u16 *)addr)[0];
if (is_wide_instruction(insn)) {
insn <<= 16;
insn |= ((u16 *)addr)[1];
decode_insn = thumb32_kprobe_decode_insn;
} else
decode_insn = thumb16_kprobe_decode_insn;
#else /* !CONFIG_THUMB2_KERNEL */
if (addr & 0x3)
return -EINVAL;
insn = *p->addr;
decode_insn = arm_kprobe_decode_insn;
#endif
p->opcode = insn;
p->ainsn.insn = tmp_insn;
switch (arm_kprobe_decode_insn(insn, &p->ainsn)) {
switch ((*decode_insn)(insn, &p->ainsn)) {
case INSN_REJECTED: /* not supported */
return -EINVAL;

13
arch/arm/kernel/kprobes.h
View File

@ -29,8 +29,21 @@ enum kprobe_insn {
INSN_GOOD_NO_SLOT
};
typedef enum kprobe_insn (kprobe_decode_insn_t)(kprobe_opcode_t,
struct arch_specific_insn *);
#ifdef CONFIG_THUMB2_KERNEL
enum kprobe_insn thumb16_kprobe_decode_insn(kprobe_opcode_t,
struct arch_specific_insn *);
enum kprobe_insn thumb32_kprobe_decode_insn(kprobe_opcode_t,
struct arch_specific_insn *);
#else /* !CONFIG_THUMB2_KERNEL */
enum kprobe_insn arm_kprobe_decode_insn(kprobe_opcode_t,
struct arch_specific_insn *);
#endif
void __init arm_kprobe_decode_init(void);